Portable writing desk



FIG. 1 is a top, left rear perspective view of a portable writing desk showing my new design, the straps depicted by means of broken lines being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a top view of the portable writing desk of the present invention;

FIG. 3 is a side view of the portable writing desk of the present invention;

FIG. 4 is a bottom view of the portable writing desk of the present invention;

FIG. 5 is a rear view of the portable writing desk of the present invention; and,

FIG. 6 is a front view of the portable writing desk of the present invention. 

The ornamental design for a portable writing desk, as shown and described. 